Taku Iwami, M.D., M.P.H., Ph.D., from the Kyoto University Health Service in Japan, and colleagues conducted a nationwide, prospective observational study involving 1,376 consecutive out-of-hospital cardiac arrest patients who received resuscitation and shocks with public-access automated external defibrillation by bystanders from 2005 through 2009.

The researchers found that 36.8 percent of patients received chest compression-only CPR and 63.2 percent received conventional CPR with compressions and rescue breathing. There was a significantly higher rate of neurologically favorable one-month survival among the chest compression-only CPR group (40.7 percent) compared with the conventional CPR group (32.9 percent; adjusted odds ratio, 1.33).

"Compression-only CPR is more effective than conventional CPR for patients in whom out-of-hospital cardiac arrest is witnessed and shocked with public-access defibrillation," the authors write.